Automatic musical instrument



C. F. STODDARD.

AUTOMATIC MUSICAL INSTRUMENT.

APPLICATlON FILED MAR. 30. 1917.

1,409,494. Patented Mar 14, T922.

/ INVENTUR;

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UNITED STATES PATENT @FFICE.

CHARLES F. STODDARD, 0F NEW/V YORK, N. 1 ASSIGNOR TU AIWERICAN' PIAN O COMPANY, 01? NEW YORK, N. Y., A CORPORATEUN NEW JERSEY.

AUTQMATIC MUSICAL ENSTRUMENT.

Specification of Letters Patent.

Patented Mar. 14, 1922.

Application filed March 30, 1917. IlSerial No. 158,592.

T 0 (1M whom it may concern Be it known that 1, CHARLES F. S'ronnAnn, a citizen of the United States of America, residing in the city of New York, in the county and State of New York, have invented an improvement in Automatic Musical Instruments, of which the following is a specification.

This invention relates to automatic means for playing musical instruments, such as pianos, and pertains more particularly to means for governing and varying tone intensities.

Among other objects the invention provides means to vary the general range of expression changes, which means may be preferably combined with automatic expression governing and regulating mechanism. Such expression governing and regulating mechanism may have, if desired, the threefold capacity for producing incremental changes in playing intensities; for maintaining uniform any given playing intensity, whether one or many notes are simultaneously sounded; and for producing substantially continuous progressive changes in playing intensities. For this purpose the invention may be. embodied in an apparatus which is very simple and reliable in operation.

For illustration, the accompanylng drawings show one practicable embodiment of the invention employing suitable pneumatically governed devices in combination with a piano action; but as will appear to those skilled in the art, the invent-ion is susceptible of embodiment in various constructions and organizations other than that particularly player pneumatic 1 is provided having a sticker 2 to act upon a wippen 3 and thereby operate the usual piano action as wellunderstood in the art. a wind chest for the motor pneumatics each of which has a secondary valve 8 controlled by a primary valve 9 operated from a tracker board T through a duct 10 in the usual manner.

The wind trunk 7 communicates with a wind chest 200 having connection with a regulated wind chest '12 through a port 201, which may now be assumed to provide unrestricted communication between the two wind chests. A high exhaust chest 14 arranged for communication with the chest 12 may be connected by a trunk 15 with any source of pneumatic exhaust, such as a diagrammatically shown feeder bellows 16, which may be of any practicable type.

lln the illustrative apparatus of the drawings, the striker pneumatics 1 may be operated by the exhaust in the wind chest 200 which will in turn be controlled by regulated exhaust in chest 12. In order to vary the operation of the striker pneumatics, this regu' latcd exhaust may be varied by subjecting it more or less to the influence of high exhaust in chest 14:. For this specific purpose a port 30 controlled by a valve 31 is provided between the high exhaust chest 14 and the regulated exhaust chest 12.

The valve 31 may be operated by any suitable means, preferably by apparatus of the general character of that herein illustrated. in this specific apparatus the stem 32 of the valve 31 is connected to a movable board 33 of a bellows apparatus presently described; said boardbeing hinged at 17. Such apparatus has a three-fold capacity for controlling "the valve 31. It automatically produces incremental changes in playing intensities; it performs a regulating function, that is, it maintains any given playing intensity whether one or many notes be sounded; and it automatically produces continuously progressive changes in playing intensities for crescendo and diminuendo purposes.

It is preferably with such apparatus that the means for varying the general range of expression changes is combined, although it A wind trunk 7 leads to will be obvious that other apparatus, having any one or all of the capacities of the apparatus herein described, may be combined therewith to advantage. Following a brief description, in the sequence indicated, of the three capacities of the apparatus acting through the bellows board 33, the embodiment of the further means referred to will be described. As the description proceeds it will be obvious that the invention is not dependent upon the specific details of construction or the specific mode of operation of the apparatus herein described.

Beneath the board 33 are three bellows 34, and 36 which have their upper boards secured to the common movable board 33 and their lower boards secured to a fixed plate 13.

Another bellows 37 has its lower board secured to the movable board 33 and its upper board to a stationary plate 38. A condition of partial exhaust is maintained at all times in the bellows 37 as presently described. The degree of exhaust in bellows 37 may be varied, but forthe present this capacity may be disregarded and the pressure within the bellows acting upon the board 33 may be considered uniform. Thus, the pressure in the bellows 37, being always less than atmospheric pressure, said bellows in effect exerts continuously a uniform upward pull on the board 33 contributing to control the valve 31.

Ducts 40, 41 and 42 enter respectively the bellows 34, 35 and 36. Each duct may be controlled by any practicable valve mechanism to admit to its bellows either atmospheric pressure, or regulated pressure from the chest 12; and regulated pressure may be admitted to the bellows selectively, while atmospheric pressure will be present in those bellows, if any, which do not contain regulated pressure. \Vhenever regulated pressure is present in any one or more of the bellows 34, 35 and 36 the effect thereof is to produce a downward pull upon the board 33. This downward pull is opposed by the upward pull which results from the condition of partial exhaust in the bellows 37, the two contributing to control the valve 31. High exhaust in the chest 14 exerts some downward pressure upon the area of the valve 31 itself; and regulated pressure in the chest 12 exerts some upward pressure upon the area of the valve. Since regulated pressure is usually greater, it generally predominates and the resultant upon the valve itself is an upward pressure which combines with the resultant of the pressure in the several bellows to complete the control of the valve 31.

The construction and arrangement of the apparatus may be such that the opposed upward and downward acting forces control the valve and tend to hold it in a balanced condition. For example, if regulated pressure be present in all three, of the bellows 34, 35 and 36. the downward pull of these bellows upon the board 33 is at its maximum and tends to close the valve 31 and minimize the opening between the chests 12 and 14. l nder these circumstances, playing intensities, as controlled by this portion of apparatus, will be at the minimum. The bellows 34, 35 and 36 will then operate substantially as a single regulator pneumatic for maintaining a uniform degree of exhaust in the regulated pressure chest whether one or many notes are concurrently sounded. A substantial uniformity of playing intensitics will thereby be maintained.

The bellows 34, 35 and 36 may be governed to vary playing intensities by varying the downward acting force which they con tribute to the control of the valve 31. If atmosphere be admitted to the bellows 36, for example, the aggregate downward pull on the board 33 is relaxed to some extent. To restore the condition of balance the degree of regulated exhaust acting upon the board 33 through bellows 34 and will be permitted to increase. Therefore the apparatus will operate to regulate playing intensities at a higher level.

Regulated pressure or atmosphere may be admitted to the several bellows 34. and 36 selectively or in combination. To those skilled in the art, it will be readily understood that several well defined grades of playing intensity may thereby be established.

Upon admitting atmosphere to all the bellows 34, 35 and 36 the forces acting upward upon the valve 31 will so far predominate as to open the valve to enlarge communication between the chests 12 and 14 to 105 the maximum.

Any suitable means may be adopted to govern that part of the -regulating mechanism which 0 crates through bellows 34, 35 and 36 to initlate different substantially dis- 110 tinct grades of regulated tension. Herein the duct 40 connects the bellows 34 with a valve chamber 50 having a port to atmos' phere and a port to a chamber 60 which is connected to the regulated pressure chest 12 115 through a passage 61. A duplex valve 51 is mounted in valve chamber 50 and is controlled by a diaphragm 52 of a diaphragm chamber 53. A duct 54 leads from said diaphragm chamber to a vent in the tracker 120 T, correspondingly numbered. The parts 50-55 described in connection with duct 40 are triplicated for ducts 41 and 42, the corresponding parts of the valve mechanism for the latter being indicated by the numer- 125 als 50, 51, etc., with indices (1- for the valve mechanism for duct 41. and I) for the valve mechanism for valve 42.

The manner in which the valves 51, 51" and 51 may be controlled from the tracker 130 erably connected to high exhaust.

will be sufficiently obvious to those skilled in the art so that a detailed description is unnecessary. Sufiice it. to say that when any one of the tracker vents is open to atmosphere the bellows corresponding thereto will also be opened to atmosphere, and when a tracker vent is closed to atmosphere its corresponding belloWs will be opened to regulated exhaust.

The preceding description has been devoted to an illustrative form of apparatus by which substantially distinct grades or degrees of regulated exhaust may be established for playing notes atsubstantially distinct grades of intensity. In an apparatus of the character described. it is preferable that the upward pull on the board 33 be maintained substantially uniform. For this purpose the preferred embodiment of the apparatus utilizes a pneumatic system, about to be described, which exerts a pneumatic pull through the bellows 37 in opposition to the bellows 34, 35 and 36; said pneumatic pull being maintained substantially uniform and corrected when necessary. For convenience in that part of the description immediately following, the capacity of the apparatus to produce incremental changes in playing intensities may be disregarded and it may be assumed .that regulated exhaust is present in all the bellows 34, 35 and 36 with the result of a maximum downward pressure on the board 33 and the valve 31.

The bellows 37 is connected by a duct 100 with a pneumatic 101, a spring 102 is fastened to the movable board of pneumatic 101 and to an adjustable screw 103 threaded in a block 104. A stop 105 is provided to limit the expanding movement of the pneumatic 101.

The pneumatic 101 may be exhausted through a duct 106 opening to a valve chamber 107 having a port 109 to atmosphere and a port 110 to an exhaust chamber 111, pref- A valve 112 is mounted in chamber 107 and is controlled by a diaphragm 113 of a diaphragm chamber 114. Diaphragm chamber 114 may be exhausted through a bleed 115 and atmosphere may be admitted thereto through a duct 116 and port 117. The opening of the port 117 is controlled by a valve 118 and, as will be readily understood, the effective opening of this port relatively to the size of the exhaust bleed 115 will control the operation of the diaphragm 113 and the valve 112, which in turn controls the degree of exhaust in pneumatic 101 and bellows 37.

Communication between pneumatic 101 and valve chamber 107 through duct 106 is somewhat restricted by an adjustable screw 119 which slightly retards the action of the valve 112 upon the pneumatic 101. Upon a slight fluctuation in the degree of exhaust in pneumatic 101 the valve 112 is automatically operated, as hereinafter described, to restore the degree of exhaust thereby, in effect, maintaining the same substantially uniform. This restoration will be slightly retarded and the operation of the apparatus in general rendered more delicate and refined because of the interposition of the obstruction 119.

For thepurpose of more rapidly restoring the intended normal pneumatic condition of pneumatic 101, a second adjustable obstruction screw 120 is likewise interposed between the valve chamber 107 and the pneumatic 101 and a by-pass around the screw 119 is provided by passages 121 and 122. \Vhen it is desired to compensate for an extreme fluctuation in the pneumatic condition of pneumatic 101, the by-pass 121122 may be opened. By-pass duct 121-122 may be closed by a valve 123 mounted upon a diaphragm of a diaphragm chamber 124. This chamber is connected by a duct 125 with a valve chamber 126 having a port 127 to atmosphere and a port 128 to exhaust chamher 111. A valve 129 controls ports 127 and 128. Normally valve 129 is seated to close exhaust port 128 and open atmosphere port 127 thereby admitting atmosphere to duct 125 and diaphragm chamber 124. This permits valve 123 to be normally seated to close by-pass 121. Upon an extreme fluctuation of the pneumatic condition in the pneumatic 101, the valve 129 is automatically lifted to exhaust diaphragm chamber 124 and open by-pass 121122, thus permitting a more rapid flow of air along duct 106.

The valve 129 is governed by diaphragm 130 of a diaphragm chamber 131 which communicates by a duct 132 with a port 133 adjacent 'the port 117; the port 133 being controlled by the valve 118. The usual exhaust bleed for diaphragm chamber 131 is provided by a bleed passage 134.

The valve 118 is operated by an arm 137 projecting from the movable board of the pneumatic 101 and is so arranged'that the port 117 will be first opened to o erate valve 112 and thereby correct any slig t variation in the pneumatic condition of pneumatic 101. Only thereafter if the expansion of the pneumatic 101 is sufficiently great, will port 133 be opened to cause a more rapid correction of the intended normal pneumatic condition.

The pneumatic 101 is controlled by the differential between the pull of the spring 102 and the action of the exhaust within the pneumatic. lVith the described arrangement of valves, these op osed forces tend to hold the pneumatic 101 1n balance. For example, the pneumatic tends to collapse to that point at which the atmosphere bleed 117 is maintained at such a capacity that the degree of exhaust in the diaphragm chamber 114 holds the valve 112 in that position in which the relative exhaust and admision of atmosphere past the valve 112 determines a degree of exhaust within the pneumatic 101 which just balances the pull of the spring 102. Any influence tending to disturb this condition of balance will be .transmit the action of said spring in such a way as to refine theregulation and render it extremely accurate. Furthermore, it is preferred that the effective area of the pneumatic 101 be somewhat greater than that of bellows 37 so that the expanding and collapsing movements of the pneumatic 101 (in response to opposite movements of the bellows 37) are much less in extent. \Vith such an arrangement the minimized .movements of the pneumatic 101 produce only slight elongations and contractions of the spring 102, and therefore produce only minimum changes in the tension of the sprin That part of the apparatus just cliascribed, in addition to IS capacity for maintaining substantial uniformity of tension upon the regulator pneumatic, (herein exemplified by bellows 34, 35 and 36) also possesses the capacity of varying playing intensities by varying the upward pull on the regulator, and of controlling this variation atdifferent speeds.

If the pneumatic 101 is collapsed beyond its position of normal self-adjustment the spring 102 will be elongated, thereby increasing its tension; and causing an accompanying increase in tension of the air contained in pneumatic 101 and bellows 37. This will result if the valve112 is raised and held in raised position for a substantial length of time, that is, until the pneumatic 101 is completely collapsed. Air will be withdrawn from pneumatic 101 through the small opening formed by the obstruction screw 119 and the increase in tension will therefore take place at a relatively slow speed.

This operation of the pneumatic 101 ultimately causes a slow increase in the upward pull of the movable board 33 and such a variation of one of the forcescontrolling the valve 31 causes a slow continuously progressive increase in, playing intensities.

If the valve 112 is. lowered to close port 110 and open port 109, atmosphere will be admitted to pneumatic 101 past obstruction screw 119 and permit a slow restoration of the pneumatic 101 to its normal position. This operation slowly decreases the upward pull on the board 33 with the ultimate result of a slow continuously progressive decrease in playing intensities.

If thevalve 129 is raised simultaneously with valve 112 the pneumatic 101 will be collapsed at a greater speed, due to the opening of the by-pass 121122. If thereafter valve 112 is lowered and valve 129 held in raised position pneumatic 101 will quickly expand. These two operations result respectively in a fast, continuously progressive increase or decrease in playing intensities.

Such changes in playing intensities as are described in the preceding paragraphs are commonly termed crescendo and diminuendo effects.

The above described operations of the valve 112 and 129 for producing crescendos and diminuendos may be controlled by any practicable means. For illustration the diaphragm chamber 114 may be connected to the tracker by a duct 138 opening to a tracker vent correspondingly numbered which may be opened or closed by perforations in a music sheet. The diaphragm chamber 131 may be similarly connected to the tracker bar by a duct 139. As will be readily understood by those skilled in the art the'regulating mechanism may thus automatically produce crescendos and diminuendos at different speeds under the control of the note sheet.

The manner of properly coordinating the operations of the several parts of the regulating mechanism under the control of a perforated music sheet will be sufficiently obvious to those skilled in the art and need not be described in detail herein.

The arts of the apparatus acting through the bellbws board 33 and having the threefold capacity for automatically producing incremental changes in playing intensities, for regulating playing intensities, and for automatically producing continuously progressive changes in pla ing intensities, having been sufiicientl escribed, the means hereinafter termed tiie re-regulator by which the range of intensity variations may be determined or limited, will now be described.

In view of the fact that the conditions surrounding the use of an automatic player piano vary greatly with every instrument, it is difficult in their manufacture to give the parts such primary adjustment as will produce the most satisfactory effects. This fact, in connection with the varying tastes of different piano users, makes it extremely desirable to have associated with the apparatus for automatically obtaining expression variations, additional means to control or vary from time totime the range of expression changes. It is often desirable to ave the playing intensity capable of autoit is impracticable to do so because such a; course would necessitate specially designed note sheets for each individual instrument. It is desirable to have the means for varying the range of expression changes capable of operation to produce different effects in the ultimate playing of the instrument at different times and under different circumstances, from the same combination of note sheet perforations. In order that the continuity of expression variations and the relative character of the expression changes may not be materially disturbed it is desirable that the means now referred to operate, not merely to eliminate certain of the expression changes, but to effectsubstantially all expression changes proportionately, thereby preserving continuity in the operation of the automatic expression governing mechanism. That part of the present invention presently to be described places the operation of the instrument under the control of the user substantially in the manner suggested above.

That part of the apparatus about to be described may also operate to vary the several'increments of intensity change predetermined by that part of the expression governing mechanism acting through bellows 34, 35 and 36. It may also operate to modify crescendo effects by reducing the loudness of playing at substantially every point in the crescendo without changing the period of the crescendo or the continuity of the crescendo progression. Diminuendo effects may be similarly modified.

In the specific embodiment of the invention disclosed in the drawings, a throttle valve 202, mounted upon a stem 203, may be properly positioned to determine the effectiveopening of the port 201, thereby restricting or enlarging the effective passage between Wind chests 12 and 200 under the control, preferably, of the means which will be later described.

The valve 202 may be operated by a variety of different means. In this specific apparatus the stem 203 is connected to an arm 201which in turn is fast to the movable board 205 of a pneumatic 206. The valve 202 is preferably so related to the port 201 that it may, if and when desired, be so positioned as to present no obstruction to the free flow of air therethrough. In such a position it will be entirely inoperative and playing intensities.

have no effect upon the determination of A compression spring 207 among other functions which will be hereinafter referred to, tends to hold the valve 202 in this normal open and non-operative position and an adjustable collar 208 may provide a convenient means for adjusting the power of the spring 207. The operative connection between the valve stem 203 and bellows arm 204 is, in this particular instance, efiected by an adjustable button 209, held in position upon the lower end of a valve stem 203 by a set screw 210.

The pneumatic 206 is connected through a valve 212 with a source of exhaust, preferably re-regulated exhaust. in the wind chest 200. A duct 213 open to the interior of the pneumatic 206 leads therefrom to the valve 212 and a duct 211 open to the wind chest 200 leads therefrom also to the valve 212. Means may be provided for varying the operative connection between these two ducts and the same will be later referred to, but for the present it may be assumed that the ducts 213 and 211 are directly connected when the re-regulator is thrown into operation.

The pneumatic 206 will be subjected to exhaust pressure and will therefore exert an upward thrust upon the valve stem 203 with a force depending upon its area, leverage, and the exhaust pressure within it. The spring 207 is preferably so adjusted that it will have a substantially constant effect throughout the operation of the re-regulator and will only predominate in controlling the re-regulator when the playing intensity is at or approaching the lowest point. Reregulated exhaust in wind chest 200 will exert a certain pressure upon the upper side of valve 202, and regulated exhaust in wind chest 12 will exert some pressure upon the under side of valve 202. The operation of the re-regulator maybe more conveniently explained if re-regulated exhaust be regarded as exerting an upward pull upon the valve 202 and regulated exhaust be similarly regarded as exerting a downward pull upon valve 202. Similarly the rarefied air in belows 206 may be considered as exerting a positive pull upon the movable board thereof. So regarding the pneumatic forces will be readily understood by those skilled in the art and will simplify the following description.

Summarizing :-The forces acting upwardly upon the valve 202, tending to close the same and thereby decrease the degree of exhaust of re-regulated air are: (1) re-regu lated exhaust acting directly upon the upper side of valve 202, and (2) re-regulated exhaust acting upon bellows 206. The downwardly acting forces tending to open valve 202 and thereby increase the degree of exhaust of're-regulated air are: (1) regulated exhaust acting upon the under side of valve 202, and (2) the spring 207; The force of gravity being constant may be disregarded. Thus, the movement of the valve 202 is controlled by the differential between the upwardly acting forces and the downwardly acting forces summarized above; and the relative areas exposed to pneumatic pressure such as the area of the valve 202 and of the pneumatic 206, (its leverage remaining constant) in conjunction with the force of the spring207 will be effective in controlling. the valve 202 so as to tend to hold it in a balanced condition. Original adjustments may be so made by the proper proportioning of the area or leverage of pneumatic 206 relatively to the area of the valve 202, and to the power of the spring, that in this balanced condition the valve 202 will restrict the opening of the port 201 relatively greater than the restriction of the port 30 by the valve 31, and this in turn will permit a relatively lower degree of exhaust in the wind chest 200 than in the wind chest 12.

For convenience of description and explanation of the re-regulator it may be assumed that the playing intensities determinable by the crescendo, diminuendo, and the incremental or step change mechanism could be measured on an imaginary scale upon which numeral 4 would indicate the lowest playing intensity while numeral 20 would indicate the loudest playing intensity. Therefore the incremental, crescendo and diminuendo changes will be effected within the compass of this scale from 4 to 20. If the apparatus is adjusted for seven defined grades of playing intensity, as might be the casewith the present apparatus, these incremental changes will be determined at points between 4 and 20. For instance, it

may be assumed that the seven steps would fix the different playing intensities respectively at 4, 4.5, 5.5, 7.5, 11,18 and 2.0 in

the imaginary scale. It may further be assumed that a. crescendo may be inaugurated when the playing intensity is-fixed at any one of the seven points in the scale, except the last, and will in operation, if continued long enough, raise the playing intensities, at a greater or less speed as may be determined by the apparatus, from the point at which it is inaugurated to the highest intensity.

Thereafter a diminuendo operation may be inaugurated and decrease playing intensities to-any point determined by the step change mechanism.

Assuming that the expression governing mechanism is set to fix the playing intensity at 20 in the imaginary scale ofintensities, and disregarding for'the moment the capacity of the apparatus for varying playing intensities from this point, let it be understood that it is desired to cut down or reduce the playing intensity Without varying the operation of the expression governing means from the tracker. It is assumedthat the appropriate original adjustments have been made. If the wind trunk 7 were connected directly to wind chest 12 the valve 31 would maintain the intensity of the sounded notes at 20, whether one or many notes were simultaneously played.- The re-regulator device is, in some respects, a second regulator interposed between the wind trunk 7 and the Wind chest 12 to regulate the degree of exhaust within the wind chest 200 relatively to the degree of exhaust within the wind chest 12. The degree of exhaust within the wind chest 12 ma be less than the degree of exhaust within t e high exhaust chest 14; similarly, the degree of exhaust within the wind chest 200 may be less than the degree of exhaust within the wind chest 12. The action of the valve 202 in restricting more or less the port 201 will be similar to the action of the valve 31 in restricting the effective opening of the port 30 but, by reason of the original adjustments, the effective opening of valve 202 may be relatively less thanthe effective opening of the valve 31.

Let it be assumed that it is desired to provide for a maximum reduction of one-half in theplaying intensities and that for this purpose the re-regulator is made operative to its full extent, then the action of the re-regulator in thus reducing playing intensities may be explained somewhat as follows: The valve 202 being free to move under the control of the several forces previously summarized, a balancing equation will be established in which the upwardly acting forces will equal and balance the opposed downwardly acting forces. equation the pressure of re-regulated exhaust multiplied by the area of the valve, plus the pressure of re-regulated exhaust multiplied by the effective area of the bellows 206, will provide a force which will equal and balance an opposed force provided b the pressure of regulated exhaust multiplied by the area of the valve, plus the force of the spring. From the above equation it will be seen that the area subjected to the pressure of re-regulated exhaust is greater than the area subjected to the pressure of regulated exhaust. Hence with a proper evaluation of the spring the areas subjected to re-regulated exhaust may be so proportioned relatively to the area subjected to regulated exhaust that the degree of re-regulated exhaust will equal onehalf the degree of regulated exhaust, and for the purpose of this description it may be assumed that playing intensities vary directly with the degree of exhaust. With the proper proportionate adjustments'of the several areas exposed to pneumatic pressure playing intensity 20 may thus be reduced to 10 in the supposed scale.

In this balancing Having described the manner in which the degree of re-regulated exhaust is reduced relatively to the degree of regulated exhaust, the manner in which this relative reduction is maintained with uniformity throughout the operation of the apparatus, (regulated exhaust being maintained as previously described) may now be considered.

In operation variations in pressure within wind chest 200 may result from a number of causes or combination of causes, but for illustrative purposes, only that variation of pressure within the wind chest 200 by reason of the operation of the playing pneumatics will be considered.

By way of illustration. assume the specific instance as stated above when regulated exhaust is maintained .uniformly to determine playing intensities at 20 and when such primary adjustments of the re-regulator have been made that re-regulated exhaust is maintained at a point to fix the playing intensity at 10. The playing pneumatics when inoperative contain atmosphere. Therefore when notes are sounded there will be a sudden influx of atmosphere to wind chest 200 increasing the pressure within said wind.chest and reducing the degree of exhaust therein. This operation will affect the factors of the assumed balancing equation by decreasing theforces tending to close valve 202; i. e. (1)

re-regulated exhaust times the area of the valve; and (2) re-regulated exhaust times the effective area of bellows 206. Therefore the resultant effect will be to open the valve 202 allowing a greater amount of air to be exhausted from wind chest 200. The regulator valve 31 will thereupon operate in the usual manner as heretofore described. When the degree of exhaust in wind chest 200 has been increased again the two changed factors in the balancing equation will be restored to their former value by this increase in the degree of re-regulated exhaust, and the balancing equation will be restored to effect the previously described relative reduction of the degree of exhaust within wind chest 200 with respect to wind chest 12.

From the above it appears that whatever drafts are made upon wind chest 200 and from whatever cause, while the pressure therein relatively to the pressure in the wind chest 12 may be momentarily varied; the relative reduction in the degree of exhaust in wind chest 200 in respect to the degree of exhaust in wind chest 12 will be restored. The restoration of the predetermined 1"ela tion of exhaust in wind chests 200 and 12 will take place so quickly as to be practically instantaneous.

The manner in which the re-regulator device may inaugurate and maintain a uniform relative reduction in playing intensities from 20 to 10 having been considered,- the operation of the re-regulator when regulated exhaust is varied by the main expression governing apparatus may now be de scribed.

Vhile the re-regulator operates to reduce the maximum playing intensity by one-half it is preferable that there be no reduction of the minimum playing intensity. \Vith the proper adjustment of the spring relatively to the other factors in the balancing equation this may be accomplished. If now the main expression governing mechanism operating through regulator valve 31, should fix regulated pressure so that the playing intensity would normally be reduced from 20 to llin the supposed scale, the re-regulator device would fix re-regulated exhaust pressure relatively to the newly established regulated pressure, thereby proportionately decreasing the playing intensity from 10 approximately to 6.6 in the supposed scale. This would take place somewhat in the fol lowing manner. Referring to the above mentioned balancing equation determining the operation of the valve 202,v the degree of exhaust within wind chest 12 pulling downwardly upon valve 202 would in this instance. be decreased. This would tend to allow valve 202 to close; the other factors remaining the same. The closing of the valve 202 will allow an increase in pressure and a corresponding decrease in the degree of exhaust within wind chest 200, due to the leakage of atmosphere thereto. The decreased degree of exhaust in wind chest 200 being communicated to pneumatic 206 the force exerted thereby tending to close valve 202 is decreased. The valve 202 will then tend to open slightly but not to its former position. Thus the principal factors of the former balancing equation are decreased proportionately to establish a new balancing equation in which the spring being constant, has an increased effect. This will result in a slightly less proportionate reduction of playing intensities that is, a reduction somewhat less than one-half (for example, from the normally regulated 11 to 6.6 upon the supposed scale). Similarly the normally regulated 7.5 will be reduced to 5.7 and so on through the various steps or different grades of playing intensity which may be inaugurated by the main expression governing apparatus. Vith the normally regulated scale as above described, that is/l, 4.5, 5.5, 7.5, 11, 18 and 20 the re-regulated scale may be 4. 4.2, 4.6, 5 3, 6.6. 9.8 and 10. It is thus apparent that the reduction varies from zero at intensity 4 to one-half at intensity 20. Obviously the foregoing figures are presented herein for illustrative purposes only.

The action of the re-i'egulator device during a crescendo or diminuendo change in playing intensities will be similar to its operation described in connection with the step or incremental changes and need not be here discussed at length, in view of'the fact that a crescendo operation gradually increases the degree of exhaust in wind chest 12 and that at any given point in the crescendo the operation of the re-regulator will be identical with its operation when an incremental change positions regulated exhaust at that point. A full crescendo operation would normally increase playin intensities from 1 to 20 in a given time. ll ith the re-rcgulator in operation the playing intensities would be increased from 1 to 10 in the same given time.

It will therefore be seen that the re-regulator device will operate automatically in response to variations in pressure within the regulated wind chest 12 and that the ultimate effect of this responsive action will be to reduce the degree of exhaust within wind chest 200 relatively to the degree of exhaust within wind chest 12, and that this proportionate reduction will be continued throughout cresc-endos, diminuendos and the several steps or grades of playing intensity which might otherwise be inaugurated by the expression governing mechanism acting through valve 31.

It has been assumed that the pneumatic 206 may be connected alternatively with a source of exhaust, for instance with the wind chest 200, or with atmosphere; thus rendering the re-regulator device operative to its full extent, whereby the'maximum playing intensity will be cut down by one-half (the proportionate reduction assumed for illustrative purposes) or rendered entirely inoperative by the admission of atmosphere to pneumatic 206. Means may be provided whereby the re-regulator device may cut down the maximum playing intensity; by a less proportion than one-half which means are herein shown as means providing for a relatively less degree of exhaust in the pneumatic 206 than in the re-regulated wind chest with which it communicates. This portion of the apparatus will now be described.

The valve 212, previously referred to, comprises a valve casing 214 having a movable piston 215 which is adapted to slide endwise in the valve and may be operated by any convenient means such as a lever 216, mounted preferably upon the key rail of the piano. The duets 211 and 213 may be opened to the interior of the valve through ports 217 and 218 respectively, while a port 219 provides for the admission of atmosphere to the interior of the valve. The valve piston is chambered to form a D valve and the valve is preferably so proportioned that the port 218 is always open to the valve chamber while the ports 217 and 219 may be placed in communication with the valve chamber by operating the lever 216. When the port 217 is wide open the port 219 will be closed. This is the position shown in the drawings and such a positioning of the valve places duct 211 in full communication with duct 213, with the result that playing intensities are reduced by the maximum reduction attainable by the operation of the re-regulator device.

It now the valve piston is moved to the right it will gradually close port 217 and open port 219 permitting atmosphere to bleed into the valve and thereby reduce the degree of exhaust in the pneumatic 206 relatively to the degree of exhaust within wind chest 200. This will decrease the upwardly acting force of the pneumatic 206 which tends to close the re-regulator valve 202 and will thereby establish a new balancing equiv tion which will so control the apparatus as to reduce playing intensities by a less amount than the predetermined maximum reduction. As the movement of the valve piston continues toward the right the port 217 will be finally closed and the port 219 opened. Thus the valve eventually cuts off all communication between wind chest 200 and pneumatic 206 and opens the latter to atmosphere. Admitting atmosphere to pneumatic 206 renders the re-regulator entirely inoperative and the playing intensities will be determined solely by the main regulator valve 31.

F or the purpose of explaining the operation of the re-regulator when the valve 212 is set to reduce playing intensities by less than the maximum reduction, a specific in stance may be assumed wherein the Valve piston 215 is positioned to shut off port 217 and open port 219 to cause the degree of ex haust in the pneumatic 206 to equal onehalf the degree of exhaust in wind chest 200. The other factors in the balancing equation of forces controlling valve 202 remain the same. Therefore a new balancing equation will be established wherein the pressure of re-regulated exhaust times the area of the valve 202, plus one-half the pressure of reregulated exhaust times the effective area of pneumatic 206, will equal the pressure of regulated exhaust times the area of the valve 202, plus the power of the spring. The relative areas and the spring remain the same so that a solution of the present equation will give a re-regulated scale of intensities substantially as follows: 4, 4.5, 5.5, 7.5, 9.6, 13.4 and 14.5. It will be noted that the first four intensities have not been reduced but that the reduction begins between intensity 7.5 and 11. Thus the apparatus will be eflfective for cutting down the louder notes by a substantial amount without affecting the finer changes in playing intensities at the foot of the scale. Crescendos and diminuendos will be similarly affected.

By the operation of the valve 212 the pressure within the pneumatic 206 may be fixed at more or less than one-half of the pressure in wind chest 200 with corresponding effects upon the playing intensities as governed by the re-regulator. The result thereby attained will be apparent to those skilled in the art from the foregoing paragraph and further explanation is deemed unnecessar rief reference has been heretofore made to the capacity of the re-regu'lator for establishing finer increments of change from one level of intensity of playing to the next, then the normally governed changes. Returning to the assumed scale of intensities it will be seen that between normally regulated intensities 4 and 11 four step changes may be made. Vhen the re-regulator device is thrown into operation to cut down the maximum playing intensity by one-half, the maximum playing intensity will be approximately 10 instead of 20, therefore six step changes may now be made between intensities 4 and 11 where only four could be made without the re-regulator device in operation.

It should be understood that in the preceding description, the scale of intensities from 4 to 20 and the corresponding reductions are assumed and arbitrary points selected merely for purposes of illustration although the lower and upper limits of the scale happen to correspond to the height to which a column of water would be drawn b the exhaust at the lowest and highest pl aying intensities respectively.

It is to be understood that the principal features of the present invention are not means herein disclosed but that the same may be variously combined with other means for normally regulating intensities and with means for producing crescendo and diminuendo changes. Furthermore the present invention is not limited to the specific details, construction, organization, and mode of operation hereinbefore described for the purpose of illustration; on the contrary, the 1nvention may be variously modified and embodied within the scope of the subjoined claims.

I claim as my invention:

1. An instrument of w the character describedcomprising, in combination, playing actions; a main source of power for operating said playing actions; a throttle valve between the main source of power and the playing actions; a regulator pneumatlc operatively connected to said throttle valve and having communication with the regulated air governed by said throttle valve; a second throttle valve intermediate the main throttle valve and the playing'actions and opening toward the main throttle valve; and a re-regulating pneumatic operatively connected with said second throttle valve and having variable communication with the re regulated air governed by said second throttle valve.

2. An instrument of the character described comprising, in combination, playing actions; a main source of power for operat-. ing said playing actions; a throttle valve between the main source of power and the playing actions; a regulator pneumatic operatively connected to said throttle valve and having communication with the regulated air governed by said throttle valve; a second throttle valve intermediate the main throttle valve and the playing actions; a re-regulating pneumatic operatlvely connected with said second throttle valve and having communication with the re-regulated air governed by said second throttle valve; and means to vary said communication between the re-regulating pneumatic and the re-regulated air.

3. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said playing actions; a throttle valve between the main source of power and the playing actions; a regulator pneumatic operatively connected to said'throttle valve and having connection with the regulated air governed by said throttle valve; a second throttle valve intermediate the main throttle valve and the playing actions; a re-regulating pneumatic operatively connected with said second throttle valve and having communication with the re-regulated' air governed by said second throttle valve; and means to admit atmosphere to said re-regulating pneumatic to thus vary the action thereof upon said second throttle valve.

4. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said playing actions; expression governing apparatus operatively connected with the source of power and the playing actions for varyin the degree of power transmitted to the actions; and additlonal expression governing apparatus operatively connected with the source of power and the playing actions, for additionally varying the power transmission in a manner which preserves the relative relation between the magnitudes of the variations produced by said expression governing mechanism, but alters the absolute value thereof.

5. An instrument of the character described comprising, in combination, playing actions; a. main source of power for-operating said playing actions; a crescendo apparatus for varying, by substantially continuous progression, the degree of power transmitted from said source to the actions; and means for varying the changes in intensity in the crescendo while preserving the time continuity of the crescendo progression.

6. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said playing actions; expression governing mechanism for varying the degree of power transmitted from said source to said actions, by perceptible increments; and means for varying the absolute increments of'change while preserving substantially the relative magnitudes thereof.

7. An instrument of the character described comprising in combination, playing actions; a main source of power for operating said playing actions; a tracker; expression governing apparatus operatively connected with the tracker to vary the degree of power transmitted from said source to the playing actions, for varying playing intensities automatically under control of a note sheet passing over said tracker; and additional means for varying the degree of power transmitted from said source to the actions, and arranged to be set in a plurality of adjustments to predetermine respectively different ranges of automatic intensity variations by said mechanisms.

8. An instrument of the character described comprising, in combination, playing actions; a main sourc of power for operating said playing actions; a tracker; two expression governing mechanisms interposed between the source of power and the actions, each to vary the degree of power transmitted form said source to the actions; means operatively connecting one of said expression governing mechanisms to the tracker for antomatically varying playing intensities under control from the tracker; and means adjustable by the operator and operatively connected with. the other expression governing means for causing the latter to predetermine the general range of intensities of playing by the instrument.

n lnstrument of the character described, comprising in combination, playing actions; a main source of power for operat ing said playin actions; a regulator operatively interposed between the main source of power and the playing actions; a second regulating mechanism including a valve interposed between the first regulator and the playing actions and having means providing an acting area exposed to regulated pressure and tending to open the valve, and means providing a greater acting area ex posed to re-regul'ated pressure and tending to close the valve.

10. An instrument of the character described. comprising in combination, playing actions; a main source of power for operating said playing actions; a throttle valve between the main source of power and the playing actions; a regulator pneumatic operatively connected to said throttle valve and having communication with regulated air governed by said. throttle valve; :1 second throttle valve intermediate a main throttle valve and the playing actions and having 'equal areas exposed to regulated and reregulated pressure respectively; means operatively connected to said throttle valve providing an additional acting area exposed to re-regulated pressure and tending to. close the valve; and means to negative the effect upon the throttle valve of said last named means when the degree of exhaust of regulated air is reduced to its minimum regulation by the first throttle valve.

11. An instrument of the character described, comprising in combination, playing actions; a main source of power for operating said playing actions; a throttle valve between the main source of power and the playing actions; a regulator pneumatic operatively connected to said throttle valve and having communication with regulated air governed by said throttle valve; a second throttle valve intermediate the first throttle valve and the playing actions. and having equal areas exposed to regulated and re-regulated pressure respectively: and means operatively connected to said throttle valve providingan additional acting area exposed to re-regulated pressure and tending to close the valve; and means to vary the degree of exhaust in said last named means relatively to the degree of exhaust of re-regulated air.

12. An instrument of the character described comprising, in combination, playing actions; means for supplying a substantially uniform degree of power for operating said playing actions; means for establishing and maintaining with substantial uniformity a reduction in said power before it acts upon the playing actions; and means for further reducing the degree of power in a manner which preserves the relative relation between the magnitudes of the variations produced by said first reducing means but alters the absolute value of said variations.

13. An instrumentof the character described comprising, in combination, playing actions; means for supplying a substantially uniform degree of power for operating said playing actions; means for establishing varying degrees of reduction of said power and adapted to maintain the degree of power reduction with substantial uniformity; and means for further reducing the degree of power in a manner which preserves the relative relation between the magnitudesof the variations produced by said first reducing means but alters the absolute value of said variations.

14. An instrument of the character described comprising, in combination, playing actions; means for supplying a substantially uniform degree of power for operating said playing actions; a. tracker; tracker controlled means for establishing and maintaining with substantial uniformity varying reductions in the degree of power before it acts upon the playing actions; and means for further reducing the degree of power in a manner which preserves the relative relation between the magnitudes of the variations produced by said first reducing means but alters the absolute value of said variations.

15. An instrument of the character de scribed comprising, in combination, playing actions; a main source of power for operating said laying actions; a tracker; tracker controlled expression governing means for varying by perceptible increments the degree of power applied, to said playing actions; and manually controlled means for varying the increments of change produced by said tracker controlled means while pre servin the relative relation therebetween.

16. n instrument of the character described comprising, in combination, playing actions; a main source of power for operating said playing actions; expression governing means controlling a port between the main source of power and a wind chest to vary by perceptible increments the degree of exhaust in said wind chest; a throttle valve interposed between said wind chest and the playing actions; a pneumatic operatively connected to said throttle valve and having connection with a source of exhaust controlled by said throttle valve; and means to bleed atmosphere to said pneumatic.

17. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said playing actions; expression governing means for altering from a base value the degree of power normally transmitted to the actions from said main source of power, thereby to determine normal playing intensities; independently operable means for varying from the established normal the degree of power transmitted in such manner that such variations bear a constant ratio to such alterations irrespective of the absolute value of said alterations, and means for changing said ratio.

18. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said playing actions; expression governing means for establishing predetermined incremental changes in the degree of power applied to said playing actions; and means for varying the absolute value of the successive increments of change in such manner that such variations bear a constant ratio to said increments irrespective of the absolute value of said increments.

19. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said playing actions; expression governing means for establishing predetermined incremental changes in the degree of power applied to said playing actions; means for reducing the increments of change so predetermined in such manner that such reductions bear a constant ratio to said increments irrespective of the absolute value of said increments; and means for varying said ratio.

20. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said playing actions; expression governing means for varying by perceptible increments or by substantially continuous progression the degree of power applied to said playing actions; and independently operable means for predetermining a plurality of substantially distinct limits for the expression variations controlled by said expression governing means.

21. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said playing actions; a wind chest having a port to the main source of power; a regulator including a valve controlling said port; a throttle valve controlling another port located between said wind chest and the. playing actions; a pneumatic operatively connected to said valve; and means providing relatively variable connections from said pneumatic to atmosphere and to a source of exhaust controlled by said throttle valve.

22. Aminstrument of the character described comprising, in combination, playing actions; power producing means; a main source of power for operating said playing actions; power regulating means for regu lating the degree of ower applied to said playing actions relatively to the degree of power supplied by the said power producing means; means for regulating the degree of power applied to said playing actions relatively to the regulation of said first named power regulating means; and further means for varying the relative regulation by said last named means.

23. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulating means interposed between said source of power and said actions; a pneumatic controlling said regulating means and normally connected to said source of power; and means to vary the tension of the power applied to said pneumatic to thus vary the action of said pneumatic on said regulating means.

24. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; a regulatlng throttle valve interposed between said source of power and said actions; a pneumatic controlling said regulating means and normally connected to said source of power; and means to vary the tension of the power applied to said pneumatic to thus vary the action of said pneumatic on said throttle valve.

25. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulatlng means interposed between said source of power and said actions; a pneumatic controlling said regulating means and normally connected to the regulated power; and means to vary the tension of the power applied to said pneumatic to thus vary the action of said pneumatic on said regulating means.

26. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulating means interposed between said source of power and said actions; a pneumatic controlling said regulating means and normally connected to said source of power; and means to bleed atmosphere to said pneumatic to thus vary the action of said pneumatic on said regulating means.

27. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulating means interposed between said source of power and said actions; a pneumatic controlling said regulating means and normally connected to'said source of power; and means to restrict the connection between said pneumatic and said source of power and simultaneously bleed atmosphere into said pneumatic to thus vary the action of said pneumatic on said regulating means.

28. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulating means interposed between said source of power and said actions; a pneumatic controlling said regulating means and normally connected to the regulated power; and means to bleed atmosphere into said pneumatic to thus vary the action of said pneumatic on said regulating means.

29. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulating means interposed between said source of power and said actions; a pneumatic controlling said regulating means and normally connected to the regulated power; and means to restrict the connection between said regulated power and said pneumatic and to simultaneously bleed atmosphere into said pneumatic to thus vary the action of said pneumatic on said regulating means.

30. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; a regulating throttle valve interposed between said source of power and said actions, a pneumatic controlling said throttle valve and normally connected to the regulated power; and means to bleed atmosphere into said pneumatic to thus vary the action of said pneumatic on said throttle valve.

31. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; a regulating throttle valve interposed between said source of power and said actions; a pneumatic controlling said throttle valve and normally connected .to the regulated power; and means to restrict the connection between said source of power and said pneumatic and to simultaneously bleed atmosphere into said pneumatic to thus vary the action of said pneumatic on said regulating means.

32. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulatlng means interposed between said source of ower and said actions; a pneumatic controlling said regulating means and normally connected to said source of power; means to restrict the connection between said pneumatic and said source of power and simultaneously bleed atmosphere into said pneumatic to thus vary the action of said pneumatic on said regulating means; and manual means for controlling said restricting means for varying the tension applied to said pneumatic.

33. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulating means interposed between said source of power and said actions; a pneumatic controlling said regulating means and normally connectedto the regulated power; means to restrict the connection between said regulated power and said pneumatic and to simultaneously bleed atmosphere into said pneumatic to thus vary the action of said pneumatic on said regulating means; and manual means for controlling said restricting means for varying the tension applied to said pneumatic.

34. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; a throttle valve interposed between said source of power and said actions; a pneumatic controlling said throttle valve; a duct leading from the regulated power; a duct leading from said pneumatic; a duct connecting with the atmosphere; and a three-way valve for connecting the duct from said pneumatic to either or both of said other ducts in varying degrees.

35. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulating means interposed between said source of power and said actions to control and vary the tension of said power; and reregulating means interposed between said regulating means and said actions for reducing the tension of said power in a manner which maintains constant the ratio between the variation in tension of the regulated power and the variation in tension of the reregulated power.

36. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; expression governing regulating means interposed between said source of power and said actions to control and vary the tension of saidpower; and reregulating means'interposed between said regulating means and said actions for reducing the tension of said power in a manner which maintains constant the ratio between the variation in tension of the regulated power and the variation in tension of the reregulated power.

37. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulating means interposed between said source of power and said actions to control and vary the tension of said power to vary the degree of force with which said actions continuously operate; and reregulating means interposed between said regulating means and said actions for reducing the tension of said power in a manner which maintains. constant the ratio between the variation in tension of the regulated power and the variation in tension of the reregulated power.

38. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulatin means interposed between said source 0 power and said actions to control and vary the tension of said power to produce a progressive change in the force with which said actions operate to thus produce a crescendo or diminuendoefi'ect in the playing; and reregulating means interposed between said regulating means and said actions for reducing the tension of said power in a manner which maintains constant the ratio between the variation in tension of the regulated power and the variation in tension of the reregulated power.

39. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said. actions; regulating means interposed'between said source of power and said actions to control and vary the tension of said power to vary the degree of force with which said actions continuously operate and to also produce a progressive change in the force with which said actions operate to thus produce a crescendo or diminuendo efiect in the playing; and reregulating means interposed between said regulating means and said actions for reducing the tension of said power in a manner which maintains constant the ratio between the variation in tension of the regulated power and the variation in tension of the reregulated power.

40. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; expression governing regulating means interposed between said source of power and said actions to control and vary the tension of said power to vary the degree of force with which said actions con tinuously operate and to also produce a progressive change in the force with which said actions operate to thus produce a crescendo or diminuendo efl'ect in the playing; and reregulating means interposed between said regulating means and said actions for reducing the tension of said power in a manner which'maintains constant the ratio between the variation in tension of the regulated power and the variation in tension of the reregulated power.

41. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulating means interposed between said source of power and said actions to control, and vary the tension of said power; reregulating means interposed between said regulating means and said actions for reducing the tension of said power in a manner which maintains constant the ratio between the variation in tension of the regulated power and the variation in tension of the rere ulated power; and means for varying Sfllf ratio.

42. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; expression governing regulating means interposed between said source of power and said actions to control and vary the tension of said power; reregulating means interposed between said regulating means and said actions for reducin the tension of said power in a manner WhlCh maintains constant the ratio between the variation in tension of the regulated power and the variation in tension of the reregulated power; and means for varying said ratio.

43. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulating means inte rposed between said source of power and said actions to control and vary the tensionof said power to vary the degree of force with which said actions continuously operate; reregulating means interposed between said regulating means and said actions for reducing the tension of said power in a manner which maintains constant the ratio between the variation in tension of the regulated power and the variation in tension of the reregulated power; and means for varying said ratio.

44. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulating means interposed between said source of power and said actions to control and vary the tension of said power to produce a progressive change in the force with which said actions operate to thus produce a crescendo or diminuendo eflect in the playing; reregulating means in terposed between said regulating means and said actions for reducing the tension of said power in a manner which maintains constant the ratio between the variation in tension of the regulated power and the variation in tension of the reregulated power; and means for varying said ratio.

45. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulating means interposed between said source of power and said actions to control and vary the tension of said power to vary the degree of force with which said actions continuously operate and to also produce a progressive change in the force with which said actions operate to thus produce a crescendo or diminuendo efi'ect in the playing; reregulating means interposed between said regulating means and said actions for reducing the tension of said power in a manner which maintains constant the ratio between the variation in tension of the regulated power and the variation in tension of the reregulated power; and means for varying said ratio.

46. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; expression governing regulating means interposed between said source of power and said actions to control and vary the tension of said power to vary the degree of force with which said actions con tinuously operate and to also roduce a progressive change in the force with which said actions operate to thus produce a crescendo or diminuendo. effect in the playing; reregulating means interposed between said regulating means and said actions for reducing the tension of said power in a manner which maintains constant the ratio between the variation in tension of the regulated power and the variation in tension of the reregulated power; and means for varying said ratio.

47. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulating means interposed between said source of power and said actions to control and vary the tension of said power; and reregulating means interposed between said regulating means and said actions for reducing the tension of said power in a manner which maintains constant the ratio between the variation in tension of the regulated power and the variation in tension of the reregulated power; and comprising a throttle valve having one surface exposed to regulated power and the other surface exposed to reregulated power and opening in the direction of the flow of the power, and a pneumatic connected to said regulated power and controlling said valve.

48. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; regulating means interposed between said source of power and said actions to control and vary the tension of said power; reregulating means interposed between said regulating means and said actions for reducing the tension of said power in a manner which maintains constant the ratio between the variation in tension of the regulated power and the variation in tension of the reregulated power, and comprising a throttle valve having one surface exposed to regulated power and the other surface exposed to reregulated power and opening in the direction of the flow of the power, and a pneumatic connected to said regulated power and controlling said valve; and a valve interposed in the connection from said reregulated power to said'pneumatic and arranged to connect said pneumatic to reregulated power or to atmosphere or to both.

49. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating'said actions; expression governing regulating means interposed between said source of ower and said actions to control and vary t e tension of said ower; and reregulating means interpose between said regulating means and said actions for reducing the tension of said power in a manner which maintains constant the ratio between the variation in tension of the regulated power and the variation in tension of the reregulated power, and comprising athrottle valve having one surface exposed to'regulated power and the other surface exposed to reregulated power and opening in the direction of the flow of the power, and a pneumatic connected to said reregulated power and controlling said valve.

50. An instrument of the character described comprising, in combination, playing actions; a main source of power for operating said actions; expression governing regu lating means interposed between said source of power and said actions to control and vary the tension of said power; reregulating means interposed between said regulating means and saidactions for reducing the tension of said power in a manner which maintains constant the ratio between the variation in tension of the regulated power and the variation in tension of the reregulated power, and comprising a throttle valve having one surface exposed to regulated power and the other surface exposed to reregulated power and opening in the direction of the flow of the power, and a pneumatic connected to said regulated power and controlling said valve; and a valve interposed in the connection from said reregulated power to said pneumatic and arranged to connect said pneumatic to reregulated power or to atmosphere or to both.

51. An expression mechanism for an automatic musical instrument comprising, in combination, an expression-controlling valve, a pneumatic operatively connected with said valve and normally open to a wind chest controlled thereby; and means to vary the degree of exhaust in said, pneumatic relatively to the degree of exhaust in said wind chest to vary playing intensities.

52. An expression mechanism for an automatic musical) instrument comprising, in combination, an expression-controlling valve, a pneumatic operatively connected with said valve and normally open to a wind chest controlled thereby; and means to vary the degree of exhaust in said pneumatic relatively to the degree of exhaust in said wind chest b admitting atmosphere to said pneumatic.

53. An expression mechanism for an automatic musical instrument comprising, in combination, an expression controlling valve, a. pneumatic operatively connected with said valve and normally open to a wind chest controlled thereby; and means to vary the degree of exhaust in said pneumatic relatively to the degree of exhaust in said wind chest by admitting atmosphere to said pneumatic in varying amounts.

54. An expression mechanism for an automatic musical instrument comprising, in combination, an expression controlling valve, a pneumatic operatively connected with said valve and normally open to a wind chest controlled thereby; and means to vary the degree of exhaust in said pneumatic relatively to the degree of exhaust in said Wind chest by admitting atmosphere to said pneumatic in varying amounts and at different speeds.

55. An expression mechanism for an automatic musical instrument comprising, in combination, an expression controlling valve, a pneumatic operatively connected with said valve and normally open to a wind chest controlled thereby; a valve from said pneumatic to atmosphere and means wherey said valve may be opened gradually to produce crescendo changes in playing intensities. I

56. An expression mechanism for an au-' tomatic musical instrument comprising, in combination, an expression controlling valve, a pneumatic operat-ively connected with said valve and normally open to a wind chest controlled thereby; a valve from said pneumatic to atmosphere and means wherey said valve may be closed gradually to produce diminuendo changes in playing intensities.

57. An expression mechanism for an automatic musical instrument comprising, in combination, an expression controlling valve, a pneumatic operatively connected with said valve and normally open to a wind chest controlled thereby; a valve from said pneumatic to atmosphere and means whereby said valve may be opened thereby to increase playing intensities.

58. An ex ression mechanism for an automatic musical instrument comprising, in combination, an expression controlling valve, a pneumatic operatively connected with said valve and normally open to a wind chest controlled thereby; a valve from said pneumatic to atmosphere and means whereby said valve may be closed thereby to decrease playing intensities.

59. An expression mechanism for an automa'tic musical instrument comprising, in combination, an expression controlling valve, a pneumatic operatively connected to and tending to close said valve; means connecting said pneumatic with a source of exhaust controlled by said valve; yielding means tending to open the valve; and means to admit atmosphere to said pneumatic to decrease the force exerted by said pneumatic which tends to close the valve.

60. An expression mechanism for an automatic musical instrument comprising, in combination, an expression controlling valve, a pneumatic operatively connected to and tending to close said valve; means adjustably connecting said pneumatic with a source of exhaust controlled by said valve, yielding means tending to open the valve; and means to admit atmosphere to said pneumatic to decrease the force exerted by saidpneumatic which tends to close the valve.

61. An expression mechanism for an automatic musical instrument comprising, in

combination, an expression controlling tie to decrease the force exerted by said valve, a pneumatic operatively connected to pneumatic which tends to close the valve.

and tending to close sald valve; means ad- In testimony whereof, I have si 'ned 111v 10 ustably connecting sald pneumatic with a name to this specification this 28th day (if source of exhaust controlled by said valve, March 1917.

a SPIlIlg tending to open the valve; and 7 means to admit atmosphere to said pneuma- CHARLES F. STODDARD.

Certificate of Correction.

It is hereby certified that in Letters Patent No. 1,409,494, granted March 14, 1922,

upon the application of Charles F. Stoddard, of New York, N. Y., for an improvement in Automatic Musical Instruments, errors appear in the printed specification requiring correction as follows: Page 11, line 126, claim 23, and page 12,

lines 9 and 20, claims 24 and 25, for the Words power applied read ewha/ust admitted; and that the said Letters Patent should'be read with these corrections therein that the'same may conform to the record of the case in the Patent Ofiice.

Signed and sealed this 13th day of June, A. D., 1922.

[smn] KARL FENNING,

Acting Gammtsstomr of Patents. 

